1. Field of the Invention
The present invention relates to an information presentation apparatus and an information presentation system for presenting information to a driver of a vehicle.
2. Description of Related Art
There is known a technique for presenting information to a driver of a vehicle through vibrating a steering wheel of the vehicle.
For example, Patent Document 1 discloses that information about traffic jam degrees, weather types at a destination or the like is presented to a driver gripping a steering wheel, by using three-level magnitudes of vibration of the steering wheel.
Patent Document 2 discloses that a seat, a steering wheel and a gas pedal are vibrated in order to present predetermined warning information to a driver. According to Patent Document 2, in particular, multiple vibrators in the seat are intermittently vibrated, so that the driver can perceive an apparent movement phenomena and can receive information as to from which direction an object is approaching the vehicle. In the above, the apparent movement phenomenon is such phenomenon that, when two or more stimuli are successively applied at different positions at short time internals, it appears to the driver that a single stimulus is moving.    Patent Document 1: JP-A-2007-55561    Patent Document 2: JP-A-2008-77631
The inventors of the present application have found out the followings.
Patent Document 1 fails to disclose a method and a configuration for presenting direction information to a driver by using a difference in magnitude of vibration of the steering wheel. The technique disclosed in Patent Document 1 cannot allow a driver to recognize the direction information. Note that the direction information is, for example, obstacle approach information (i.e., information as to from which direction an obstacle is approaching the vehicle), vehicle travel direction (i.e., information as to in which direction the vehicle should travel according to route guidance) or like.
In a human body, since peripheral nerve for transmitting stimulation is concentrated on palms and fingers, the palms or fingers contacting with a steering wheel can allow clearer perception of stimulation as compared with a back or a femoral area contacting with the seat. Thus, the apparent movement phenomena generated by the stimulation takes place remarkably at the palms and fingers contacting with the steering wheel, compared with the back or the femoral area contacting with the seat.
However, Patent Document 2 fails to disclose that object approach direction information (information as to from which direction an object is approaching the vehicle) is presented using vibration of multiple vibrators in the steering wheel although Patent Document 2 discloses that the object approach direction information is presented using vibration of multiple vibrators in the seat. Therefore, the technique disclosed in Patent Document 2 cannot allow a driver to clearly recognize the object approach direction information.